Jan Mischke

11 Questions 25 Answers 0 Followers

Questions related from Jan Mischke

Adhesion problems of Al/Ni on p-GaN after RIE etching?

Hello, I am trying to structure p-GaN-layers by RIE-etching. Therefor I use a 200 nm Al/ 200 nm Ni etching mask. However, after the etching process (ICP plasma, I use Cl and N2 suring the etching...

13 March 2019 130 4 View

Why don't I see a 2D-Peak in Graphene while D-Peak is present?

Hello, This is a more theoreticall question: The D and 2D band correspond to the same phonon (iTO @ K-point). So it's the same breathing mode. How come, that I can have different Raman spectra...

19 March 2018 3,520 7 View

Increasing sheet resistance in graphene after annealing step?

Hello Community, I am struggeling at the moment with the correct concept of the link between the sheet resistance of graphene and the improvement of the dirac point after a annealing step. So...

16 January 2018 9,896 0 View

Origin of non-emitting regions above a "insulating" substrate in a CH4/H2 plasma?

Hello Community, I am working with a CH4/H2 Plasma in a cold-wall reactor. If I use conducting substrates (like metalls) there is a homogeneous plasma visible above my substrate (roughly 1-2 cm...

19 October 2017 2,000 2 View

Where does the dark space in plasma above non-conducting substrate come from?

Hi, I am using a pulsed DC plasma (~10 kHz pulsing frequency) with CH4 and H2 in a simple plate condenser set up. I use pressures of a few mbar and temperatures of 700°C-900°C. If I use non...

01 June 2017 8,011 5 View

Where is the difference in Hall measurements between 3D and 2D samples?

Hello, Hall measurements with Hall bar geometries are well understood for bulk materials. My question is: Can you translate the common bulk equations for RH, the carrier concentration and...

02 February 2017 6,843 6 View

What are these strange structures during graphene growth?

I am growing graphene on copper foil and then transfering it on SiO2-substrate. If I have a look onto it with SEM I see these strange structures. Raman says that the brighter spots are graphene...

14 November 2016 1,555 5 View

Raman spectroscopy of CVD Graphene directly on as grown Copper foil?

Hi, I am trying to characterize some PECVD Graphene samples on copper foil. Because transfer on SiO2 substrates is a time intensive process, I would rather try to characterize the samples via...

09 June 2016 5,981 13 View

How can I achieve ohmic contacts to p-GaN core-multishell nanowires?

I am trying to contact core-multishell GaN nanowires with a n-doped core and a p-doped multishell radial around the core via E-Beam lithopraphy. To characterize them I tried to realize ohmic...

11 December 2014 1,508 7 View

Where does the contrast in SEM images of 2D-Materials come from?

I am trying to understand the contrast difference between 2D-Materials (namels graphene) and the underlying susbtrate (e.g. SiO2 or germanium). Using an SE2-detector you get topographical...

01 January 1970 5,448 3 View

Dependency of the plasma power in a H2 plasma from the H2:CH4 ratio?

Hello Community, I am currently trying to grow graphene via plasma enhanced chemical vapor deposition. Therefore I use a reactor with a pulsed DC plasma source. During my plasma tests I made some...

01 January 1970 7,764 10 View